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finfo_open

finfo::__construct

(PHP >= 5.3.0, PHP 7, PHP 8, PECL fileinfo >= 0.1.0)

finfo_open -- finfo::__construct — 创建新 finfo 实例

说明

过程化风格

finfo_open(int $flags = FILEINFO_NONE, ?string $magic_database = null): finfo|false

面向对象风格（构造器）：

public finfo::__construct(int $flags = FILEINFO_NONE, ?string $magic_database = null)

本函数打开一个魔数数据库并且返回它的实例。

参数

flags

一个 Fileinfo 常量或多个 Fileinfo 常量进行逻辑或运算。

magic_database

魔数数据库文件名称，通常是 /path/to/magic.mime。如果未指定，则使用 MAGIC 环境变量。如果未指定此环境变量，则使用 PHP 绑定的魔数数据库。

传入 null 或者空字符串，等同于使用默认值。

返回值

（仅适用于过程化风格）成功时返回 finfo 实例，或者在失败时返回 false。

更新日志

版本	说明
8.1.0	现在返回 finfo 实例，之前返回 resource。
8.0.3	`magic_database` 现在可以为 null。

示例

示例 #1 面向对象风格

<?php
$finfo = new finfo(FILEINFO_MIME, "/usr/share/misc/magic"); // 返回 mime 类型

/* get mime-type for a specific file */
$filename = "/usr/local/something.txt";
echo $finfo->file($filename);

?>

示例 #2 过程化风格

<?php
$finfo = finfo_open(FILEINFO_MIME, "/usr/share/misc/magic"); // 返回 mime 类型

if (!$finfo) {
    echo "Opening fileinfo database failed";
    exit();
}

/* 获取指定文件的 mime 类型 */
$filename = "/usr/local/something.txt";
echo finfo_file($finfo, $filename);

/* 关闭资源 */
finfo_close($finfo);
?>

以上示例会输出：

 
text/plain; charset=us-ascii

注释

注意:
通常来说，除非特别需要自定义的魔数数据库。否则使用绑定的魔数数据库（不设置 magic_file 和 MAGIC 环境变量）是最好的做法。

参见

finfo_close() - 关闭 finfo 实例

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User Contributed Notes 10 notes

down

illusivefingers at gmail dot com ¶

11 years ago

I am running Windows 7 with Apache.  It took hours to figure out why it was not working.

First, enable the php_fileinfo.dll extension in you php.ini. You'll also need the four magic files that are found in the following library:

http://sourceforge.net/projects/gnuwin32/files/file/4.23/file-4.23-bin.zip/download

An environment variable or a direct path to the file named "magic" is necessary, without any extension.  

Then, make sure that xdebug is either turned off or set the ini error_reporting to not display notices or warnings for the script.

Hope this saves someone a few hours of frustration!

down

Anonymous ¶

10 years ago

For most common image files:
<?php
function minimime($fname) {
    $fh=fopen($fname,'rb');
    if ($fh) { 
        $bytes6=fread($fh,6);
        fclose($fh); 
        if ($bytes6===false) return false;
        if (substr($bytes6,0,3)=="\xff\xd8\xff") return 'image/jpeg';
        if ($bytes6=="\x89PNG\x0d\x0a") return 'image/png';
        if ($bytes6=="GIF87a" || $bytes6=="GIF89a") return 'image/gif';
        return 'application/octet-stream';
    }
    return false;
}
?>

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olivier dot berger at it-sudparis dot eu ¶

12 years ago

On my Debian squeeze system, the path needed is like :
<?php 
 $finfo = new finfo(FILEINFO_MIME, "/usr/share/misc/magic.mgc");
?>

down

ian at createanet dot co dot uk ¶

16 years ago

Couldn't get finfo to return the mimetype in the way expected so i made a function to do it with system()

<?php 
function get_mime_type($filepath) {
    ob_start();
    system("file -i -b {$filepath}");
    $output = ob_get_clean();
    $output = explode("; ",$output);
    if ( is_array($output) ) {
        $output = $output[0];
    }
    return $output;
}
?>

hope it works for other people too

down

dario dot borreguero at gmail dot com ¶

15 years ago

Platform: WinXP-SP2, PHP5.2.5, MySQL 5.0, Apache 2.2.8

After reading former notes, I wasn't able to load my magic database: 'magic.mime' file (donwloaded from GnuWin32 project, zipped with the binary files v4.21). I always got an invalid $finfo object or finfo_open(...) returned FALSE.

In order to be able to load the 'magic.mime' file, Fileinfo library (bundled in PHP5.2.5) also requires 'magic' file.

For example:
1. Database:
  c:\php\magic.mime
  c:\php\magic

2. PHP Code:
<?php
  $filname = 'c:\php\php.ini';
  $finfo = new finfo(FILEINFO_MIME, 'c:\php\magic');
  if (!$finfo) return false;
  echo $finfo->file($filename);
?>

For further info see: http://pecl.php.net/bugs/bug.php?id=7555

Pay attention to comments added by 'christophe dot charron dot xul at gmail dot com'

NOTE: Before upgrading to PHP5.2.5, I was working with PHP5.2.1 and it only required 'magic.mime' file.

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php at brudaswen dot de ¶

15 years ago

Since it costed me some time to find the needed magic database files for Windows, just a hint:

The last release of the GnuWin32 project with both needed files (magic and magic.mime) currently was "file-4.23".
All releases after 4.23 to 4.25-1 did not contain both needed files.

Hope that helps.

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php at kingsquare dot nl ¶

15 years ago

The current version (1.04) doesnt support a different mime.magic database than the server default.

(the documentation is thus not correct)
Ubuntu default location is '/usr/share/file/magic'. In order for the examples to work all finfo_open()-commands must be issued with the extra location accordingly:
<?php
$file = "/path/to/file.jpg";
$handle = finfo_open(FILEINFO_MIME, '/usr/share/file/magic');
$mime_type = finfo_file($handle,$file);
?>

down

-1

mark at dynom dot nl ¶

15 years ago

It seems there is quite some inconsistency in distributions and loading of magic files.

On Archlinux, the file is located here:
/usr/share/misc/file/magic.mgc

But this:

<?php
$fi = new finfo(FILEINFO_MIME, '/usr/share/misc/file/magic');
$fi->file('/tmp/fubar.txt');
?>

Actually segfaults, where if I type the full name (including the file extension:)

<?php
$fi = new finfo(FILEINFO_MIME, '/usr/share/misc/file/magic.mgc'); // added ".mgc"
$fi->file('/tmp/fubar.txt');
?>

It works as expected, so I guess something goes wrong with "A .mime and/or .mgc suffix is added if needed."

down

-4

tularis at php dot net ¶

16 years ago

On Windows systems people might find that this always returns "application/x-dpkg".
There are 2 ways of solving this problem:
1. Get the mime-magic database file from GnuWin32 at <http://sourceforge.net/projects/gnuwin32/>
2. You can manually "fix" the mime-magic file by editing it and escaping all lines starting with !, thus changing each one to \!

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-8

franssen dot roland at gmail dot com ¶

13 years ago

Notice FileInfo::__construct() has strange behavior in PHP < 5.3.1 when a 2nd parameter is set explicitly, e.g.;

<?php
$fileInfo = new finfo(FILEINFO_MIME, null);
?>

Expected result:
----------------
object(finfo)#2 (0) { }

Actual result:
--------------
Warning: finfo::finfo(): Failed to load magic database at ''. in *** on line ***
object(finfo)#2 (0) { }

See http://bugs.php.net/bug.php?id=51732

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